Useful conveyances with inexpensive plastic wheels are ubiquitous. In the home, for example, most households have utilitarian wheeled garbage or recyclables carts. Many households also have more luxurious wheeled barbeques or wheeled furniture. Similar products are in the workplace as well.
In many applications, such products are subject to a harsh environment and use, with minimal or no maintenance. Trash or recyclables carts may be left outdoors permanently and are thereby subject to extremes of temperature and sunlight. Moreover, rough handling is common, such as that which occurs when loaded garbage carts roll over curbs and other obstacles.
Typically, such carts are formed of injection, blow, or rotationally-molded plastic and have injection, blow, or rotationally-molded plastic wheels, which are mounted on the ends of a metal axle by a hub member. To hold the wheels in place, the wheel hub is secured onto the end of the axle in place by, for example, a pawl nut or a cotter pin and washer. Removal of such plastic wheels in order to replace or repair the same has been difficult because the hubs require special tools for their removal or essentially must be destroyed to remove them from the axle. Sometimes this process also damages the axles. Thus, more recently, wheel-mounting assemblies have been devised which snap onto the axle or axle stub to hold the wheel to the axle.
Snap-on wheel-mounting assemblies, however, often have been unduly complex, visually unappealing or not well suited to the shock loading and vibration, which is commonly encountered in connection with wheeled refuse carts. Moreover, the cost of many snap-on couplings has been undesirably high, as has their rate of failure.
Typical wheel-mounting assemblies can be seen in U.S. Pat. Nos. 2,978,277, 3,907,370, 5,222,786, 5,603,555, 5,716,107, and 6,170,920.
In U.S. Pat. No. 2,978,277 to Gaudry, a two-piece hub assembly is used to secure a wheel on an axle stub. The two hub halves are forced together to simultaneously capture the head of the axle and a dove-tailed cross section of the wheel. This approach is based, in part, upon mating frictional engagement of the hub halves, but under shock loading and high vibration, which refuse carts typically experience, frictional engagement of components can be unreliable. The need for multiple hub pieces and an axle with an enlarged head also is not desirable.
The wheel-mounting assembly of U.S. Pat. No. 3,907,370 to Bard employs a mounting sleeve, which is keyed to slide over the keyed end of a specially formed axle. The sleeve mates with spokes in a wheel recess and is held in place by a washer and cotter pin. An annular cap is placed over the cotter pin and washer. This approach requires axle keying, a plurality of parts and the use of tools to secure and release the cotter pin and cap.
A multiple piece hub assembly is shown in U.S. Pat. No. 5,716,107 to Parker et al. In this wheel-mounting assembly a retainer member is used to lock the wheel assembly on a groove or annular notch at the end of the axle. The hub cover is snapped into the wheel and then the wheel snapped onto the axle. Such notched or grooved axles are in wide spread use in connection with trash carts, but this assembly, again, requires multiple pieces and, in this case, special tools and tedious manipulation are required in order to release the resilient retainer ring fingers from the inside of the wheel so that the wheel can be removed from the axle.
The devices of U.S. Pat. Nos. 5,222,786 and 5,603,555 employ sleeve assemblies formed for mounting through the wheel in telescoped relation over the axle. The device of U.S. Pat. No. 5,603,555 has a sleeve with at least one snap-acting, axle-engaging shoulder thereon which releasably retains the sleeve on the axle and at least one wheel-engaging shoulder retaining the wheel on the sleeve. Both of the wheel-mounting sleeve assemblies in these patents, however, are relatively complex and employ a plurality of pieces in order to secure the wheel on the axle.
U.S. Pat. No. 6,170,920 to Markling shows an axle retainer assembly having a housing with transverse sleeves that support an axle and a spring biased retainer pin that mounts to an annular groove at the axle. The spring and retainer pin are separate, and the housing is supported in a cavity formed in a wheel spoke. Just as with the devices of U.S. Pat. Nos. 5,222,786 and 5,603,555, Markling disadvantageously employs multiple pieces in order to secure the wheel on the axle.
Accordingly, there is a need for a wheel assembly and wheel-mounting sleeve that can be used to mount plastic wheels, or the like, to a relatively simple notched metal axle.
Moreover, there is a need for a plastic wheel assembly for a trash cart or the like which is economical to manufacture, easy to mount and compact so as to allow its use on a wide variety of different refuse carts, and is durable and capable of withstanding substantial shock loads, side-to-side shifting and vibration during normal use. Should degradation or failure occur, there is a further need for products that may be removed to enable repair or replacement of the wheel assembly with a minimal number of parts.